I am happy to announce that the next batch of kWeld is in production. I accept pre-orders through my shop. All pre-order products are on sale with a 10% discount until Nov 30.

I totally underestimated the demand, and ran out of stock by just pre-orders in less than a week. I plan another batch right after having received the current one. I'll inform again through the newsletter. But in order help me estimate the demand, I have just implemented an "inform me on availability" button for the sold out products that puts you on a waiting list when you click it.

Defiantly looking forward to your design changed and advancements. Nice job. FYI: The KZfaq video links on your web site just load your website again.

Very nice, the best spot welder around.

I just bought one, had no idea they had been around this long I thought like 3 years at tops. Means that its a very good spot welder.

Very nice idea. Well done, but bad used money. What abou supercapacitor Maxwell 2,7V 350F.

Ah! I was looking for this spot welder kit but you didn't turn up in my searches. I ended up buying a different one. -_-

great fun and well done!

Could I use a 12volt deep-cycle marine battery to power the welder? I have several of these batteries I maintenance-charge via solar panels, and think would be perfect. I want to make a battery pack for my e-bike, using .18mm nickel strips; will your welder do this? I like the idea of NOT having to rely on the powergrid to do welding (read: portable). Thank you for what looks like an outstanding product. Wes

Dumb question; but why not make a piece to hold both electrodes in place, and make this a one handed tool, so that the other hand can keep the metal strip in place? You'd also get more consistent spacing, and possibly save time.

I think it would be even better if you would use a STM32 and so you just connect it directly to the computer, it shows up as a storage, you drop the file in the folder, disconnect and it automatically flashes itself.

Very, very cool. Excellent work. I will be ordering one for myself at some point. I have ordered some nickel ribbon and I just need to find a good supplier of quality 18650’s in Canada.

Have you thought about using some decoupling capacitors for the input-side? I would imagine having a capacitor that stores ~100J would also drastically decrease the burden on the power-source and likely increase efficiency due to lower ESR. The reason i think this would help is quit simple: The capacitor can be charged over a longer period of time (hundreds of miliseconds) and during the burst the battery would "only" need to deliver a part of the total current. So lower current bursts on the battery, lower resistance for the discharge. I would make the potentiometer logarithmic: Going form 30 to 60 joules can change a lot, but from 400 to 450 not really, so imo it would be better to have tighter control at lower levels. Also: as i think it will be mostly used for battery strip welding - why not make a small connector that has the anode/cathode close to each other in a single piece, maybe even with a springloaded switch so you can align it and only when you push it down hard will it make an actual connection?

Is the spotwelder pulsing one time or two times in quick succession? When doing two pulses, first small, second big, you burn away the oxide layer. This creates a better weld. Have you experimented with this?

I just tested my K-Weld from 18650'ed. I used a 6s Chevrolet Volt homemade lipo, and made approx. 100 test welds without fail. It is a single 6 cell 15.5 Ah NMC-LMO LG battery beginning @ 24.9v. Wonderful results, with an average of 1650A per 50ms weld. Given above approximations, should I expect about a solid 60 seconds of weld time until discharged? Would you say yes, or less? Ir is 1.6mOh / cell. I never liked the reliability record of the HK Nano-Tech.

Ouch, that battery may do well short term but I can't imagine it lasting too long at almost double it's rating.

Did you weld any thing, at all? Or we assume that you welded some thing on the long metal bar? Shady dialogue. Thanks, though.

OK, I see your website is back up. I'm only a little concerned that I see no real feedback from anyone. I looked on the ES post, and figured at least Spinningmagnets would of given a review by now considering he got one. Maybe I'm not looking in the right place for feedback comments? Irregardless, I'll probably be pre-ordering one by the end of next week. I'm wondering what buss bars to expect, brass or aluminum? Also, what the expected shipping date may be? I just signed up for the newsletter.

Hello! Thank you for this project. I get my kit HW R3.3 yesterday 28.09.23 - did I get it with the newest version of FV or it need to be updated??

Excellent work dear fellow! Question: Why would you not use a DC breaker instead of a fuse?

A Very nice Spotwelder, it seems very well designed & made of a "very high quality" for the price. 😊👌👍 I recently purchased a K-Weld Spotwelder, which im actually just waiting for it to be delivered. Im wanting to power the Spotwelder by either 2 ways Option 1 - Could I run it through a K-Cap capacitor bank then off to a "Normal Variable Bench Power Supply" ? I have a DIY 240V AC Variable Bench Power Supply with output specs: 0- 44V DC 0-20A With fine Variable increments & Constant Voltage & current settings. Would this be adequate enough to power the Spotwelder through the Capacitor Bank ? Option 2 - I may run this K-Weld spotwelder off some - Headway 38120S "HP" 8Ah cells in a 4S / 3P configuration, these Cells can deliver up to 200A "Continuous"per cell so a 4S/ 3P battery would deliver around 13.2V at 24Ah Capacity & 600A "Continuous" so should see peak current far higher than this. Would this work adequately ?? I know I could use your recommended 3S lipo battery but I thought this battery type & current rating (I mentioned above) would be a much safer chemistry (lifepo4) & also last far longer (lifespan) under these high current & demanding surge conditions. What are you thoughts ? And which way would you prefer out of these two options. Any help would be greatly appreciated, Thankyou 😊🙏

hi do you know where to get Kweld this days because Germany and America not sending to UK.thanks

This is way out of my budget so I'm gonna DIY one... But do you know if 1000VA of 24VAC rectified power supply would be suitable? I have a variac in front of those and I can over volt them just a bit so I can have any voltage between 0 and 30. I will obviously put a FULL BRIDGE RECTIFIER, not a puny single diode rectifier on it, but would I need some smoothing capacitors on that part?

When will they be in stock again? This is exactly what I'm looking for! Feel free to message me.

What about a 3D printed electrode handle that keeps them a couple of millimeters apart, so you can hold both with one hand? Could just be slip fit, and maybe tilted at a slight angle.

Very impressive I definitely want one.. is everything you have shown here available now?

Does the current version use the same block and is the software up to date ?

Are these still for sale? I don’t see any of your posts very recent. Have you given up making them?

May i suggest if your building a quality made spot welder... buy a more quality made LIPO and preferable a hardcase one instead of a softpack which is more prone to accidental punctures.

did you test with two lipo batteries in parallel? You should get cool currents and low times.

Damn, I wanna buy a full kit. ;) I wonder when would pre-order be available?

anquino??

can we use a 12v car battery? you must find an easier way to make on/off of the welder without the need to unplug the battery each time. maybe an extra high amp switch?

179 usd is just too much, but it is a nice welder you made.

currently looking at your welder and the arduino spot welder. However, I cant find any comparisons between the two. Can you elaborate on any advantages your model offers over theirs. Not trying to put you on the spot, but just want to get all the info before I pull the trigger on one. Kind regards.

So where can i get one of those then

Is your spot welder able to weld copper sheet 0.2mm to cell 18650?

I ordered one here in the US just have a question about the battery. What is the voltage range the unit works off of. Can I use a 4S battery or can it only be a 3S? Can you make a video going over the menu controls please?

No actual trial test in the video?

Do you have an assembly video?

How can those wire put out 1400 amps??????

Do you sell these spot welders already built? If so can you tell me the price, please!!

it might be good to use an encoder instead of a potentiometer

Error: 'remove short' ??

new stock is coming, and I've just opened for pre-orders at the shop! --> www.keenlab.de/index.php/product-category/kspot-welder-kit/

Excellent! Please let me know when I can place an order.

You need copper. All that brass and aluminum is lossy. Brass is only 28% as conductive. Aluminum is like.... Really bad.

Anyone using supercaps for this? Maxwell seems to have some good ones

I can not get to the site: kicksurfer.de. May I order one from here in the USA with out going to that site please?

When can I buy one it’s late August😕 I can’t wait 😁

Hi there where or how can I purchase one of this ?

I'd rather have copper buss bars

Hi thanks for the helpful information. I guess you are from Germany from your accent.. Would you be able to help me source the aluminium bus bar ? I live near Germany ( und ich kann auch Deutsch reden ; )

Hello Great project please list on ebay you will get more sales. a lot of people will not be bothered or trust every little shop that pops up promising they will keep your banking details safe.

Nice project. I suggest you re-asess the battery choice though. Turnigy uses a Li-Co chemistry that has high power density, but relatively low discharge cycles. For this application you don't care about weight: it's not a drone. And LiCo is not that safe if you abuse it. There's no way you should be using a battery if you even START to get it swelling. Not indoors. And I don't believe they actually get 5000 mAh for a 3S1P system: that's not possible for this chemistry. I suggest you consider LiFePhosphate, specifically made by A123 of USA. In a 26650 format. They have long cycle life (>1,000 vs < 300 for LiCo) and very good peak discharge: better than LiCo. And are much safer if you abuse them. See this review: lygte-info.dk/review/batteries2012/A123%2026650%202500mAh%20(Green)%20UK.html You can buy them from US sources at reasonable cost in bulk: USD13 each plus shipping (flat rate shipping charge that is high for a few units, but OK if you order a lot). So you can have a better battery for less cost, as well as much safer, good max discharge and MUCH longer life. You don't need a BMS if you monitor the battery voltage (re-charge when battery gets to 2Volts each, ideally before), and you already have your fuse to prevent too high a discharge. You can use these batteries (A123 LiFePhosphate 26650) without a BMS if you charge them on a cell by cell basis, and even if you don't do that. All of the Lithium motorbike starter batteries use this system, and many have no BMS. You can use a simple constant current/voltage power source to charge each 26650 cell at 3.9V and 2amps. It goes very fast: and they self discharge to level out at 3.8V (no load).

Why not a machined copper bar for the FETs instead of aluminium?

!!

Do you provide a schematic?

As I see all you do is turn on/off bunch of MOSFETs connected in parallel using a microprocessor. What so special about it? And you can just use regular car battery. Those are capable of similar currents. No reason to waste 60 bucks on a lipo pack for soldering purposes.